There is an alternative solution.........
Bear in mind that the inside of a PC is a very hostile place for Audio signals, particularly for low level signals such as Microphone inputs. There is a terrific amount of electrical noise generated within a PC - both radiated (airborne) and conducted via the power supply connections to either the onboard audio system or any Plug-In cards.

In the past, I used an external Analog to Digital module - Creative Soundblaster 24bit - which connects to a PC via the USB port and also is powered via the USB port. This unit produced superb results during conversion of Tapes and LPs to CD. I could not detect any background noise on the CDs, even during quiet passages within the music, unlike the results I achieved when using an Internal Plug-in Audio card of good quality.

The unit is not expensive - Currently around $45 US and you can read more about it here :
http://www.amazon.com/Creative-Labs-SoundBlaster-24-Bit-External/dp/B00030099O

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Willum

After silence, that which comes nearest to expressing the inexpressible is Music.
Aldous Huxley